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Chronic sympathetic denervation of the pineal gland by bilateral removal of the superior cervical ganglia (SCG) was performed on female rats 30 days before impregnation. The offspring, maintained in the dark from birth, had disruption of the malate dehydrogenase circadian rhythm in the testes at 25 days of age. A daily injection of melatonin (1 mg/kg s.c. at 10:00 or 18:00 h) to denervated mothers from the 14th day of pregnancy up to the 10th day postpartum produced one daily phase in the enzyme activity of tests in the offspring. Entrainment of daily enzyme activity also was obtained when the hormone was administered orally to the pups during the postnatal period or when pups were reared by intact (not denervated) foster mothers. The results indicate the involvement of the maternal pineal gland in the maternal transfer of photoperiodic information necessary for the coordination of the circadian system in young rats.

Glycerol-3-phosphate dehydrogenase (GPDH) isozymes are differentially expressed among tissues and during flight development. GPDH-1 is involved in the flight-muscle metabolism and GPDH-2 provides precursors for lipid biosynthesis in many tissues. We have isolated and characterized from Triatoma infestans, a Chagas disease vector, two cDNAs encoding for GPDH-1 and GPDH-2 isozymes. The inferred amino acid sequences showed high identity with other GPDH sequences from flying insects. A GPDH-2 transcript was found in fifth instar nymphs, thoracic muscles, adult gonads, and fat bodies. Both isozymes are present in 30-day-old adult thoracic muscle transcripts, and the pattern of expression differs between sexes. The expression of GPDH-1 begins earlier in females, and GPDH-2 is expressed more abundantly in female adult thoracic muscles than in those from males. This finding is consistent with those of other investigators who showed a higher flight initiation probability in T. infestans females than in males.

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Abstract. Flight muscles of Triatoma infestans have two glycerol-3-phosphate dehydrogenase (GPDH) isoforms: GPDH-1 is involved in flight metabolism and GPDH-2 provides lipid precursors. Total GPDH activity was greater in the natural population and almost only due to GPDH-1. Different expression and activity observed between GPDH isoforms in the natural population and the first laboratory generation was not detected in the second laboratory generation. This pattern may be caused by gradual adaptation to laboratory nutritional conditions. During development, the expression of GPDH-2 increased with a longer time of intake, which would imply an increment in lipid biosynthesis. The GPDH-1 transcript predominated with respect to that of GPDH-2 in the lower nutritional condition, suggesting the necessity of insects to fly during this nutritional status. The transcriptional pattern showed a delay at 22 C. The isoforms activities and transcript patterns in flight muscles suggest transcriptional adaptation to metabolic requirements originated by alternative splicing.

Malate dehydrogenase activity and soluble protein content in testes from rats exposed to a 14:00 h light:10:00 h dark photoperiod, have been determined every two or four hours over a 24 hour period in 5, 15, 25 and 120 day-old rats.By using the Cosinor method, the ontogeny of an unimodal rhythm was studied for MDH activity and soluble protein content in testis. In 5 and 15 day-old rats, the MDH acrophases were recorded around 19:00 h and 17:00 h, respectively. Rats aged 25 and 110 days showed the MDH acrophases during the dark period. An inversion of the MDH circadian rhythms was detected in 25 day-old compared to those of 5 and 15 day-old rats. An inversion of the protein circadian rhythm was also detected at 15 days compared to that at 5 days. These inversions persist in the adult rats. The amplitude of the MDH and protein rhythms reached the lowest value in adulthood. The mean daily value of testicular MDH increased between day 5 and 15, decreasing at day 35 and remaining unchanged until adulthood.The variation of malate dehydrogenase activity, soluble protein content levels, and the circadian rhythm parameters during the maturation process may be related to gonad development.