Journal of Chemical Ecology, VoL 8, No. 5, 1982

CONSTITUENTS OF TEMPORAL GLAND SECRETION OF THE AFRICAN ELEPHANT,

Loxodonta africana

J.W. W H E E L E R , 1 L.E. R A S M U S S E N , 2 F. A Y O R I N D E , 1 I.O. B U S S , 3 and G . L S M U T S 4"5 1Department of Chemistry, Howard University Washington, D. C. 20059 2Oregon Graduate Center, 19600 N. IV. Walker Road Beaverton, Oregon 97006 3Department of Zoology, Washington State University Pullman, Washington, 99163 4National Park Board Skukusa, 1350, South Africa sCurrent address: Natals Park Board, P.O. Box 622, Pietermaritzburg, South Africa. (Received February 5, 1981; revised September 29, 1981) Abstract--Temporal gland secretion (TGS), obtained from I5 different mature African elephants in Kruger National Park was analyzed for volatile constituents. Only five volatile components were present, p-Cresol was present in all samples, but phenol was found as an appreciable component of only one sample and as trace amounts in six others. Three sesquiterpenes were identified, the latter two being new natural products: E-farnesol, farnesol hydrate (3,7,11-trimethyl-2,10-dodecadien-l,7-diol), and farnesol dihydrate (3,7,11-trimethyl-2-dodecen-l,7,11-triol). These sesquiterpenes represent the first isolated from mammals. Ten samples of TGS, serum, a.nd saliva were assayed for cholesterol, urea, and proteins including several enzymes.

Key Words--African elephant, Loxodonta africana, temporal gland secretion, farnesol, sesquiterpenes, phenol, cresol, cholesterol, proteins, urea.

INTRODUCTION

The temporal gland is an organ uniquely possessed by African elephants

(Loxodonta africana, Blumenbach) and Asiatic elephants (Elephas maximus, L.). The ancient mammoth (Mammathus primigenius, Blumenbach) also 82t 0098-0331/82!05004)821503.00 9 1982PlenumPublishingCorporation

822

WHEELER ET AL.

possessed temporal glands that probably were larger than those of modern elephants (Pocock, 1916), the glands of which weigh from 230 to 1590 g in bulls of various ages. The gland is located on the side of the head in the temporal fossa about midway between eye and ear, and opens to the surface by a duct near the center of its lower border. Temporal glands of proboscids were first reported in 1734 (Perrault) and are well known as mixed (sebaceoapocrine) skin glands. The sebaceous part occurs superficially, whereas the apocrine part is deep and comprises most of the gland. The gland's secretory activity was reported to be related to the mating period and reproduction, but more recently this has been denied (Short, 1966; Sikes, 1971; Eisenberg et al., 1971). Current reports (Eisenberg et al., 1971; Sikes, 1971; McKay, 1973) propose this organ as a potential scent gland (as are most apocrine glands) which possibly has a dual function. The opportunity to obtain biological data on the African elephant will not be available long, particularly if the dramatic increase in poaching of wild elephants fostered by skyrocketing ivory prices throughout the world continues. This could result in the African elephant being relegated to an endangered species, further reducing the opportunity to secure data from wild stock. Such data could be of taxonomic significance when compared to closely related species. Since the elephant is generally known to be comparable with man in growth rate, life span, and time of onset of puberty, studies of biochemistry could have some pertinence to humans. We believe that a compilation of constituents of temporal gland secretion from the African elephant will be of considerable value to scientists interested in elephants. Therefore, the twofold purpose of this report is to present both volatile and nonvolatile constituents of the African elephant's temporal gland secretion and to suggest functions for this secretion. Buss et al. (1976) showed that the organic and inorganic biochemical parameters measured for temporal gland secretion were consistent within a limited range in all cases except protein and cholesterol levels. Additional measurements of total, free, and esterified cholesterol are reported for TGS, serum, and saliva for ten more recent samples in the current study. Protein studies include electrophoretic separation of lipoproteins, glycoproteins, and LDH (lactic dehydrogenase) isozymes. Adams et al. (1978) reported the analysis of temporal gland secretion volatiles from the African elephant. These authors, who sampled only one or two elephants, found phenol, m-, and p-cresol to be the major volatile components. They also reported the presence of more than 40 components in all gas chromatographic traces and indicated that one of these may be indole. We have analyzed the temporal gland secretion from a larger number of elephants (15) and find only five volatile components in this secretion.

TEMPORAL GLAND OF ELEPHANT

823

METHODS AND MATERIALS

Sample Collection. All samples for this study, like those reported by Buss et al. (1976), came from elephants harvested for management purposes in Kruger National Park, South Africa. For volatiles analyzed by GC-MS (Table 2), samples were used from 15 elephants (8 females) from 9 to 60 years of age collected over a two-year period between April 1976 and June 1978 (Table 1). Samples from many of the same elephants, as well as samples from those reported in 1976, were used for the nonvolatiles analyzed. All elephants were stimulated into temporal glandular secretion by helicopter driving from where they were located to the nearest service road. There they were killed by overdoses of saturated succinyl choline chloride solution, eviscerated, and loaded for transport to an abattoir. Temporal gland secretion was collected by insertion of a heavy-gauge blunt stainless-steel needle about 3 cm into the temporal duct. The needle was connected to a 50-ml glass syringe. As the secretion flowed, it was recovered into the syringe. The samples were sealed in glass vials, placed in a glass thermos with ice and then frozen (-20~ within an hour and shipped on dry ice. GC-MS Analysis of Folatiles. Thawed samples were extracted three times with Burdick and Jackson methylene chloride, the extracts dried over anhydrous sodium sulfate, and the solutions analyzed directly by combined gas chromatography-mass spectrometry on a Finnigan 3200 GC-MS. Columns (1.6 m x I mm) containing 3% OV-17 and 10% SP-1000 on Supelcoport 60/80 were temperature programed at 10~[min from 50 to 200~ (300~ for OV-17). Proton magnetic resonance spectra were obtained on a Nicolet NT-200 superconducting spectrometer utilizing 5-ram tubes. Preparative gas chromatography was accomplished on a Glowall 320 gas chromatograph equipped with an argon detector using a 1% OV- 17 column (1.6 m X 5 ram) on Supelcoport 60/80. Analysis of Nonvolatiles. Measurements and assays included protein (Lowry et al., 1951), total cholesterol (Allain et al., 1974; Witte et al., 1974), cholesterol esters (Webster, 1962), urea (Archibald, 1945), alkaline phosphatase (Bessey et al., 1946), amylase (Rinderknecht et al., 1971), LDH (Amador et al., 1965), and peroxidase (Matkovics et al., 1977). Enzymes were assayed in triplicate and expressed as #M / hr/mg protein. Polyacrylamide gel electrophoresis was by the methods of Gorovsky et al. (1970) and Wardi and Michos (1972) and included LDH isozyme visualization by the method of Storey (1977). RESULTS

VoIatiles. Only five compounds were detected, even at extremely high gain and elevated temperatures, in contrast to the 40 volatiles previously

F F F plb

F1 F1 M F1 F1 F M F F M F F

F pl M M M M M

1340 1341 1347 1348 1349 1350 1351 1352 1353 1356 1364 1402

1477 1522 1523 1524 1525 1526

Sex

1289 1303 1316

Number

08/18/77 08/17/77 08/18/77

06/10/78

06[09/78

04/25/78 06/05/78 06/07/78 06/08/78

08/17/77

9 14 16 24 33 36 25 28 26 26 25 25

08/15/77 08/15/77 08/15/77 08/15/77 08/16/77 08/17/77

03/17/76 04/07/76 04/15/76

Date

26 38 14 14 21 9

25 60 28

Age

aSecretion flow c o m m e n c e d during helicopter drive. bp: pregnant; I: lactating. e+, noticeable odor; +% strong odor. d_, n o material or observations received.

Family unit o f 9 Family unit o f 9 Family unit o f 9 Family u n i t o f 8 Family unit o f 8 Family u n i t o f 10 Family unit o f 10 F a m i l y unit o f 10 F a m i t y u n i t o f 10 F a m i l y unit o f 10 F a m i l y unit o f 10 1978 Family unit Bull group o f 2 Bull group o f 9 Bull group o f 9 Bull group o f 5 Bull group o f 2

1976 Family unit F a m i l y unit Family unit 1977

Groups

4 30 15 30 15 4

2 5 1.5 1.5 2.5 2.5 8 5 10 -

10 15 15

A m o u n t (ml)

+ ++ +

+

++c +

Odor

Secretion a

T A B L E 1. SAMPLE SIZES FROM 21 E L E P H A N T S C O L L E C T E D IN 1 9 7 6 - 1 9 7 8

tight lgt-br brown light light brown

red~r light

Color

+ + +

+ +

+ + + + +

d -

Serum

+ + + +

-

-

+

+ -

_ -

Saliva

FOR CHEMICAL A N A L Y S E S

Temporal gland

t"

OQ tO 4~

825

TEMPORAL GLAND OF ELEPHANT

TABLE 2. VOLATILE COMPONENTS OF TEMPORAL GLAND SECRETION a

1289 F 1303 F 1316 F 1341 F 1349 F 1352 F 1353 F 1477 F 1351 M 1356 M 1522M 1523 M 1524 M 1525 M 1526 M

Phenol

Cresol

Farnesol

Fa~nesol hydrate

p tr tr tr

m m x m x x m x x x x m p x p

tr m x p p x x x x m x p x x

tr x x p rn x x x p p x x

tr tr tr -

Farnesol dhhydrate p p p p m p

am = major (>50%); x = minor (20-49%); p = present (2-19%); tr = trace (

Constituents of temporal gland secretion of the African elephant,Loxodonta africana.

Temporal gland secretion (TGS), obtained from 15 different mature African elephants in Kruger National Park was analyzed for volatile constituents. On...
752KB Sizes 0 Downloads 0 Views