Enzyme histochemical studies of the general body surface apocrine glands in the domestic cat]

With enzyme histochemical methods, the distribution and the activities of various oxidative and hydrolytic enzymes in the apocrine glands of the general body surface of the domestic cat were investigated. The results obtained support the view that these glands are clearly active in function. On the whole, however, the relatively weak enzyme activities in the secretory portion of the glands point to only unimportant secretion production rates.     

Fusion of lipid bilayers: a model involving mechanistic connection to HII phase forming lipids.

A model for the molecular mechanism of the fusion of lipid bilayers is described. A crucial feature of this model and related to the lamellar-->hexagonal phase HII transition is a novel, hypothetical lipid conformation, tentatively referred to here as extended. During fusion this conformation could manifest itself in the contact site between two vesicles in close proximity and involves the extension of the acyl chains of a phospholipid molecule in opposite directions, i.e. embedded into the two opposing bilayers while maintaining the headgroup in the interface. Although evidence for the occurrence of the extended conformation for phospholipids is sparse this conformation appears to be compatible with currently available experimental data. Of importance also is that the extended conformation allows for the fusion of two bilayer membranes to proceed with minimal exposure of the lipid hydrocarbon chains to water. It can also account for other features of membrane fusion such as lipid mixing in the intermediate state without mixing of the vesicle contents as well as for the molecular basis of the action of fusogenic lipids.     

Sexual behavior and serum hormone levels in aging rhesus males: effects of environmental change

Old (N = 9) and middle-aged (N = 9) rhesus males (Macaca mulatta) that were housed in the same type of home cage and the same room for several years were moved to a new location in an adjacent building. Their sexual behavior and hormone levels in the weeks preceding the move were compared to those after the move. The hypothesis that the nonspecific sensory stimulation provided by the move would increase levels of sexual behavior was not supported by the data. To the contrary, the percentages of tests with contacts, mounts, and penile erections, and the rate of contacting the female, decreased significantly for both old and middle-aged males. The intromission rate of middle-aged, but not of old, males also decreased. In consonance with previous findings, middle-aged males displayed significantly higher levels of sexual activity than did old males. The differences were observed both before and after the move. Serum testosterone levels did not differ between middle-aged and old males, and the move did not produce significant changes in testosterone levels. Serum cortisol levels were significantly higher immediately after the move (1 hr) but returned to premove levels the following day.