H. Hormonal Influences upon Exocrine Glands

The growth and elaboration of exocrine sebaceous glands are facilitated by androgen (Straus and Ebling, 1970), and this is partioularly well documented in certain specialized sebaceous glands which are involved in the exploration/marking and offense behaviors of muroid rodents. According to the extensive research of Thiessen and Yahr (1977), the specialized midventral sebaceous gland of the Mongolian gerbil is larger in the male than the female, and its size is androgen-dependent; i.e., it practically disappears after castration, but is reinstated to pre-castration levels by the injection of androgen. Mid-ventral gland size in the female Mongolian gerbil is not responsive to estrogen or progestin, but it does increase in response to androgen injections and during the period of lactation, perhaps as a function of circulating levels of' prolactin. The flank glands of the golden hamster are also much larger in males than in females, a difference that may be abolished by castration and reinstated by the administration of androgen (Kupperman, 1944; Hamilton and Montagna, 1950). There is an entire category of male accessory reproductive glands in muroid rodents that are responsive to both organizing and activating influences of androgen. These glands, that appear in a bewildering array across various muroid rodent species (Arata, 1964) and that may be quite different even within the same genus (Linzey and Layne, 1969), include the bulbo-urethral, preputial, ampullary, vesicular, and prostate glands. Some of the variability has been attributed to the role of these glands in production of a copulatory plug that is present in some muroid rodents but not in others (Hartung and Dewsbury, 1978), but it is also possible that these glands playa role in the secretion of diversified pheromones.

Estrogen may also activate the glandular secretion of specialized pheromones in some species. In the golden hamster vaginal secretions that function as attractants and sexual excitants for males are under control of estrogen (Orsini, 1961; Brom and Schwartz, 1968).

Androgens alter the quality of secretions from the sebaceous glands of muroid rodents so that they function as specific, androgen-dependent pheromones. As such, they may have specific effects as motivating stimuli upon various motivational systems including offense, defense, exploration/marking, and sex. Urine from norma1 ma1es, containing the secretions of the male accessory reproductive glands, is a powerful motivating stimulus for the offense motivational mechanism of other conspecific males. This effect is dependent upon androgen, as demonstrated by the fact that urine from the following categories of "donors" provokes offense when painted onto a standard test opponent: intact male mice (Mugford and Nowell, 1970) and golden hamsters (Payne, 1974b); ovariectomized females treated with testosterone (Mugford and Nowell, 1971b); and castrated males treated with testosterone (Haag et a1, 1974). In contrast, urine from the following categories of donors provokes less offense: castrated males without testosterone (Mugford and Nowell, 1970; Payne, 1974b); and normal females in various states of estrus (Payne, 1974b; Haag et a1, 1974). Normal males or castrates injected with testosterone produce a urinary pheromone that inhibits exploration/marking in other conspecific males, and the pheromone is lacking in castrates without androgen (Jones and Nowell, 1973; Gawienowski et a1, 1976). In addition there are data that odors from intact males are more attractive to females than odors from castrates in rats (Carr et a1, 1965) and mice {Orsu1ak and Gawienowski, 1972), which we have attributed to their action on an estrogen-activated olfactory filter,

Estrogen may alter the quality of urine and sebaceous gland secretions so that they function as specific, estrogen-dependent pheromones. As in the case of male pheromones, they may function as motivating stimuli for various motivational systems including offense: and exploration/marking. Urine from normal females is an inhibitory motivating stimulus for offense, and the effect is apparently dependent upon estrogen. When the urine is taken from normal female "donors" (Dixon and Mackintosh, 1971; Mugford and Nowell, 1971b) or from ovariectomized females administered estrogen (Haag et al, 1974), it suppresses offense when painted onto a castrate male opponent. When the urine comes from an ovariectomized female donor, however, it is not effective (Haag et a1, 1914). Urine from estrous females is a more powerful attractant to experienced males than urine from anestrous females, presumably as a function oŁ the estrogen levels at estrus. This has been demonstrated in the laboratory rat (Carr et al, Stern, 1970; Lyde11 and Doty, 1972), laboratory mouse (Hayashi Kimura, 1974), and golden hamster (Singer et aI, 1976).

Although ACTH may stimulate growth of exocrine glands under experimental conditions, the effect under natural conditions may be quite different. ACTH increases the size of preputial glands in adrenalectomized rats (Jacot and Se1ye, 1951), suggesting a direct stimulation of the glands. Under conditions of population stress, however, pituitary-adrenal activity would be expected to be maximal, the preputial glands are reduced in size (Davis and Christian, 1957). It would appear that the reduced androgen levels during stress are a more important factor than ACTH.

Prolactin may also facilitate the production of specific pheromones of the lactating female that serve as attractants to her offspring (Moltz, 1974).

References A-B

References C-H

References J-P

References Q-Z

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