EFFECT OF Α-Melanocyte-Stimulating HORMONE AND OVARIAN STEROIDS ON PREPUTIAL GLAND FUNCTION IN THE FEMALE RAT

Abstract

Sexually experienced male rats were used to test the attractiveness of preputial gland odours of female rats. The male rats showed a clear preference for the preputial gland odours of hypophysectomized females given oestradiol benzoate (OB) for 3 or 8 days to those of control rats. Progesterone treatment had no effect on the attractiveness of the preputial gland odours of OB-treated hypophysectomized female rats. Administration of alpha-MSH for either 3 or 8 days, on the other hand, increased the attractiveness to male rats of preputial gland odours of OB-treated hypophysectomized females and the presence of progesterone produced no further change. When administered alone alpha-MSH had no effect on the attractiveness of the preputial gland odours. Other pituitary hormones, such as ACTH and prolactin, had no effect on the attractiveness of preputial gland odours of OB-treated hypophysectomized rats when administered for 3 days. An increase in preputial gland size was only seen when OB, progesterone and alpha-MSH were administered together. It would appear that no relationship exists between the size of the preputial glands and their ability to attract male rats. It is concluded that, while alpha-MSH and progesterone may be important in controlling growth of the preputial glands, an interaction between alpha-MSH and oestrogen is more important for regulating the production of sex attractants by the preputial glands.

Melanocortin-5 Receptor Deficiency in Mice Blocks a Novel Pathway Influencing Pheromone-Induced Aggression

“…Requirements for prolonged melanocortin treatment and preputial hypertrophy in the proximal melanocortin stimulation of aggression might indicate an increase in biosynthesis and release of aggression-stimulating pheromones that exert selfstimulating effects. Our results are consistent with evidence demonstrating that while alpha-MSH and sex steroids are important in controlling growth of the preputial gland, interaction between alpha-MSH and sex steroids is more important for regulating preputial biosynthesis and secretion of lipid compounds, including pheromones (Chen et al, 1997;Cooper et al, 1975;Donohoe et al, 1981;Ebling et al, 1975;van der Kraan et al, 1998). In the present study, NDP-MSH was administered and behavioral testing occurred in the middle of the light phase.…”

Male Genital Tract

“…102 They possess a behavioral role through the release of pheromones. They are bilateral and located in the adipose tissue lateral and cranial to the penis.…”

Pharmacology of the Skin I

“…While testosterone may affect both cellular proliferation and lipogenesis, tx-MSH acts predominantly on the latter and, in particular, on wax ester biosynthesis (COOPER et al 1974;). cx-MSH and oestrogens may nevertheless act synergistically to stimulate the secretion of preputial gland odours (DONOHOE et al 1981). tx-MSH also acts synergistically with progesterone to stimulate sebum secretion and preputial gland size (KRAHENBUHL and DESAULLES 1969;THODY and SHUSTER 1975) but has no such effect with the oestrogens.…”