Rats were weighed, and the length and width (to nearest 0.1 mm) of the right testis was measured at 2-wk intervals until 12 wk of treatment, and thereafter at longer intervals. During testis measurements, the rats were lightly anesthetized with isofluorane (Ohmeda PPD Inc., Liberty Corner, NJ) maintained as necessary with methoxyflurane (Pitman-Moore, Inc., Mundelein, IL). Testis volume was estimated using the formula for a prolate spheroid (width2 X length X 0.523), which is highly correlated with testis weight in our hands. Because testes are somewhat compressible in a live animal, producing a potential subjective component to testis measurements, all measurements presented for this experiment were taken by a single person (LMY) blind with respect to treatment. Buy Asthma Inhalers Online
This experiment tested whether the biologically reasonable challenge of mild food restriction could trigger facultative enhancement of reproductive inhibition by SD. Forty male Fischer 344 rats (Charles River Laboratories, Raleigh, NC; gestated and born in 12L:12D), aged 22 ± 2 days, were assigned to one of four weight-matched treatment groups: LD and ad lib food (RMH 3000) (LD-ad lib), SD and ad lib food (SD-ad lib), LD and FR (LD-FR), and SD and FR (SD-FR). All rats were held in a single room in fan-ventilated photoperiod chambers (86 X 58 X 49 or 160 X 69 X 40 cm) lit by 20-W fluorescent bulbs (illuminance of 200-250 lux 5 cm above the floor of the cage). Temperature within the boxes was 23 ± 2°C.