Ovaries from guinea pigs of different ages have been examined by light microscopy. Serous cysts measuring between 1 mm and 2.5 cm are present in all animals over one year of age. The cysts are fewer in number and size at six months, are least developed at ten weeks and are not apparent in the near-term fetus. The cysts arise from the rete ovarii. They are lined with a simple cuboidal to columnar epithelium composed of cells bearing solitary cilia or tufts of cilia. The structure and origin of these cysts is discussed and compared with what is known of the human serous cystadenoma.

Serous cysts of the aging guinea pig ovary. I. Light microscopy and origin.

The ability of isolated adrenocortical cells to secrete corticosterone in response to ACTH challenge declines as rats age, but the site or mechanism(s) of this impairment is still unknown. To test the functionality of steroidogenic capacity per se, we measured the key enzyme activities involved in corticosterone biosynthesis. We also measured the mitochondrial cytochrome P-450 content and nonsteroidogenic enzymes specific for subcellular fractions. Mitochondria and microsomal fractions were isolated from the adrenals of 2-, 12-, and 18- month-old animals and used for various enzyme measurements. Mitochondrial side-chain cleavage enzyme activity (nanomoles per min mg protein-1) increased from a mean of 0.43 ± 0.06 in 2-month-old rats to 1.26 ± 0.11 and 1.51 ± 0.06 in 12- and 18-month old rats, respectively. After incubation with 5- cholesten-3j8,25-diol (25-hydroxycholesterol; 25 μg/ml) sidechain cleave activity rose to 5.0 ± 0.6, 12.4 ± 1.2, and 16 ± 1.4 nmol min-1 mg protein-1 in adrenal mitochondrial fr...

The influence of age on steroidogenic enzyme activities of the rat adrenal gland: enhanced expression of cholesterol side-chain cleavage activity.

Cyclic changes in behavior or activity on the part of eukaryotes in general, correlated to the oscillations in light, temperature, and other variables that characterize the planet on which they live, have become an extremely important area for investigation during the post-1950 period. Circadian and photoperiodic changes related to the day-night pattern have proven especially fertile fields, but infradian (several cycles per day), lunar, and circannual ones have also been productive. A large majority of the investigations have been descriptive of physiological state variations at the organismic level and thus provide only indirect clues that alterations in gene function govern the activities; nevertheless, such studies do serve to reveal the great abundance and wide divergence in character of biorhythms, or chronobiological phenomena, as cyclic behavior has become termed. Nearly all the important life functions have proven to be rhythmic in character, including cell division (Scheving and Pauly, 1973), diapause, energy metabolism, reproduction, sleeping and waking, feeding, types of nutrients consumed, and even the manner of death in man as suicide, coronary disease, and stroke (Kripke, 1974; Reinberg, 1974; Rutledge, 1974; Gorski et al., 1975; Sachsenmaier, 1976; Wever, 1979). But many of lesser importance, such as otolith formation in fish (Barkman, 1978; Dunkelberger et al., 1980; Mugiya et al., 1981), and auditory brain stem response in man (Marshall and Donchin, 1981), also have proven to be rhythmic in occurrence on a daily basis.

Gene Expression Changes in Cyclic Functions

Pregnant Mare Serum and Human Chorionic Gonadotropin Stimulate Ovarian ∆5-3β-Hydroxysteroid Dehydrogenase in Aged Mice

The steroidogenic potentials of testes from 6-mo-old and approximately 28-mo-old CB6F1 mice were compared by measuring the secretion rate of 11 steroids produced by testes perfused in vitro. Testes from 6- and 28- to 30-mo-old mice secreted similar amounts of testosterone, but marked differences in the secretion of testosterone biosynthetic intermediates were discovered. Testes of old mice produced significantly more (P less than 0.01) delta 5-steroids than young male mouse testes. The presence or absence of sexual activity among old male mice was not correlated with changes in testicular steroidogenesis or plasma steroid levels. The results suggest that selected alterations in androgen biosynthesis occur during aging, but that the decline in reproductive performance among old mice is not attributable to deficits in testicular steroidogenesis. Rather, age-associated losses in sexual activity may be mediated by disturbances in the central nervous system.

R. D. Koos

Papers

Ageing and adrenal delta5-3beta-hydroxysteroid dehydrogenase in female mice.

Ovarian Δ5-3β-Hydroxysteroid Dehydrogenase and Cholesterol in the Aged Mouse During Pregnancy