Young, middle-aged and old rat adrenal gland steroidogenesis was measured in isolated, superfused glands and in their subcellular fractions before and after adrenocorticotropic hormone treatment. In the latter experiment, five corticosteroids were extracted from six different subcellular fractions. Superfused glands initially produced relatively high glucocorticoid levels; thereafter, production decayed asymptotically. Steroidogenesis by young and middle-aged glands was maintained at least 1.5 to 2.5 hours before it decayed; old glands were 50% less active than younger ones and production decayed within one hour. High cholesterol and progesterone levels in certain old gland fractions were associated with correspondingly reduced 11-deoxycorticosterone and corticosterone. It is suggested that synthesis of these glucocorticoids from their accumulating precursors weakens with age.

This study concerned the effect of ethanol on cardiac activity and brain respiration in chick embryos. Ethanol dosages tested ranged from 1.0 mg to 4.0 mg/g weight. Each experiment lasted at least 150 minutes. Cardiac activity in terms of total waveform energies was integrated and printed out for plotting and analysis. The embryonic heart rates were simultaneously determined from physical graph tracings. The embryonic brain respiration was measured using a differential microrespirometer. The effect of ethanol on cardiac activity was one of slight (10 to 13), but statistically significant (p<.05) rate depression. The brain slices exhibited a marked, immediate, and irreversible decrease (39 to 89%) in oxygen consumption at both ethanol dosages. The data indicated that chick embryonic brain tissues were more susceptible to alcohol effects than cardiac tissue. Therefore, the mental abnormalities seen in the offspring of alcoholic mothers may be more cerebral in nature than cardiovascular.

Stability of the macrobenthic community in a regulated section of the Brazos River, Texas, was evaluated. Physicochemical data and information on spatial distribution of macrobenthos were collected. Populations of two invertebrate species, Isonychia sicca and Neoperla clymene, had been greatly reduced since 1970-71 and I. sicca had been practically eliminated from this section of the Brazos. Three other insect populations, Choroterpes mexicanus, Cheumatopsche campyla and Cheumatopsyche lasia, had more than doubled their numbers since the 1970-71 study. A physicochemical gradient existed in this regulated section of the Brazos but it appeared to have changed little in comparison of earlier chemical data. A gradation of the macrobenthic community was evident as distance from the dam increased,