Comparative studies on the contents of vitamin D3, 25-hydroxy vitamin D3 and 7-dehydrocholesterol in fish liver

Tiwari

et al. 1997

Braz J Med Biol Res

Vitamin D 3 (100 ng 100 g body weight -l day -l ) was administered intraperitoneally (ip) to the freshwater mud eel Amphipnous cuchia kept in artificial freshwater, calcium-free freshwater, low-calcium freshwater (0.2 mmol/l CaCl 2 ) or calcium-rich freshwater (13.4 mmol/ l CaCl 2 ) for 15 days. Analyses of serum calcium and phosphate levels were performed on days 1, 3, 5, 10 and 15 after the beginning of the experiment (six eels from each group at each interval). Administration of vitamin D 3 elevated the serum calcium [maximum elevation occurred at day 10 in artificial freshwater (vehicle: 10.55 ± 0.298, vitamin D: 13.90 ± 0.324), low-calcium freshwater (vehicle: 11.17 ± 0.220, vitamin D: 12.98 ± 0.297) and calcium-rich freshwater (vehicle: 11.24 ± 0.373, vitamin D: 14.24 ± 0.208) whereas it occurred at day 5 (vehicle: 8.42 ± 0.253, vitamin D: 11.07 ± 0.328) in calcium-free freshwater] and phosphate levels [maximum elevation at day 15 in artificial freshwater (vehicle: 4.39 ± 0.105, vitamin D: 5.37 ± 0.121), calcium-free freshwater (vehicle: 4.25 ± 0.193, vitamin D: 5.12 ± 0.181), low-calcium freshwater (vehicle: 3.93 ± 0.199, vitamin D: 5.28 ± 0.164) and calcium-rich freshwater (vehicle: 3.77 ± 0.125, vitamin D: 5.46 ± 0.151)] of the fish maintained in the above mentioned environmental media, but the responses were more pronounced in the fish kept in calcium-rich media.

Section: Introductionmentioning

confidence: 99%

Vitamin D3-induced calcemic and phosphatemic responses in the freshwater mud eel Amphipnous cuchia maintained in different calcium environments

Tiwari

et al. 1997

Braz J Med Biol Res

Okajimas Folia Anatomica Japonica

“…The fact, that (i) vitamin D is stored in fish liver (Takeuchi et al , 1987), (ii) fish plasma does contain a transport protein for 25-OH-D3 (Hay and Watson, 1976) which is the primary circulating form of vitamin D in mammals, (iii) the presence of a renal 25-hydroxyvitamin D-1-hydroxylase in the kidneys of fish (Henry and Norman, 1975), (iv) presence of 25-OH-D3 and 1,25-(OH)2D3 in the plasma of shark and trout (Glowacki et al , 1982) and (v) hypercalctirnia reported after vitamin D or its metabolite administration to fish (Srivastav, 1983;Swarup et al, 1984;Fenwick et al, 1984); leave little doubt that vitamin D and its metabolites can affect calcium homeostasis in fish.…”

mentioning

confidence: 99%

Vitamin D3- Induced Histological Changes in the Corpuscles of Stannius of a Freshwater Catfish, Heteropneustes Fossilis Kept Either in Artificial Freshwater, Calcium-rich Freshwater or Calciumdeficient Freshwater

Singh

Kumar

1996

Summary: Vitamin D3 (50I.U./100 g body wt) was injected day intraperitoneally to the fish H. fossilis maintained in artificial freshwater, calcium-rich freshwater and calcium deficient freshwater. The animals were killed on day 1, 3, 5, and 10. The serum calcium levels were estimated and CS were fixed for histological studies.Administration of vitamin D3 induced hypercalcemia in the fish kept in all the three different media.The AF-positive cells of CS of vitamin D3 treated specimens kept in artificial freshwater, calcium-rich freshwater and calcium-deficient freshwater depict hyperactivity which is expressed by their degranulation and increased nuclear volume.The AF-negative cells of CS of vitamin D3-treated fish kept in artificial freshwater have not shown any change, however, the AF-negative cells of the fish treated with vitamin D3 and maintained in calcium-rich freshwater and calciumdeficient freshwater exhibit a decrease in their nuclear volume.Corpuscles of Stannius (CS) are endocrine tissue which exist only in the kidneys of some holostei and teleostei. Functional aspects of this gland is not yet well understood but the studies of Wendelaar Bonga and

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

“…Earlier studies reported a lack of any relation between provitamin D3 and vitamin D3 contents in several fish (10,11,14) and also that the levels of these two compounds in the skin of fish were lower than those of rats (15), suggesting that the photochemical synthesis of vitamin D3 might not be significant in fish. It has been * To whom correspondence should be addressed .…”

Section: Discussionmentioning

confidence: 99%

“…On exposure to sunlight, the 5,7-diene of 7-DHC (steroid) absorbs ultraviolet (UV) energy (spectral range 290-315nm) that causes the cleavage of C9-C10 bond in the "B ring" to form vitamin D3 (secosteroid) (5-7) . Thus, "sunlight" is the chief energy source for breaking the B-ring of steroid in land animals.Interestingly, certain fish liver oils are rich sources of vitamin D [25,000 250,000IU/g oil (8-11)] when compared to mammals [<1IU/g oil (12)], inspite of the non-availability of enough UV light in their natural habitats (13).Earlier studies reported a lack of any relation between provitamin D3 and vitamin D3 contents in several fish (10,11,14) and also that the levels of these two compounds in the skin of fish were lower than those of rats (15), suggesting that the photochemical synthesis of vitamin D3 might not be significant in fish. It has been * To whom correspondence should be addressed .…”

mentioning

confidence: 99%

Vitamin D3 in Tilapia mossambica: Relevance of Photochemical Synthesis.

Rao

Raghuramulu

1997

SummaryThe capability of fish to synthesize vitamin D on exposure to ultraviolet (UV) light was examined. Purposeful exposure of the freshwater fish Tilapia mossambica (Tilapia) to artificial UV light (300 nm) resulted in a significant increase of vitamin D3 with a concomitant decrease in provitamin D3 ], indicating that provitamin D3 was coverted to vitamin D3. However, only 0.13% of the intraperitoneally injected 4-14C cholesterol was recovered in the vita min D3 and 25-hydroxyvitamin D3 (25-OH-D3) fractions after 15h of irradiation. Thus, although fish is capable of photosynthesizing vitamin D through constant, prolonged exposure to UV light of appropriate wave length, the contribution of this mode of synthesis is unlikely to be of any significance in its natural habitat. Key Words photochemical, Tilapia, vitamin D3, 7-dehydrocholesterol, 25-OH-D3It is well known that vitamin D3 in land animals is mainly derived from photochemical conversion of provitamin D3 (7-DHC) in the skin (1-4). On exposure to sunlight, the 5,7-diene of 7-DHC (steroid) absorbs ultraviolet (UV) energy (spectral range 290-315nm) that causes the cleavage of C9-C10 bond in the "B ring" to form vitamin D3 (secosteroid) (5-7) . Thus, "sunlight" is the chief energy source for breaking the B-ring of steroid in land animals.Interestingly, certain fish liver oils are rich sources of vitamin D [25,000 250,000IU/g oil (8-11)] when compared to mammals [<1IU/g oil (12)], inspite of the non-availability of enough UV light in their natural habitats (13).Earlier studies reported a lack of any relation between provitamin D3 and vitamin D3 contents in several fish (10,11,14) and also that the levels of these two compounds in the skin of fish were lower than those of rats (15), suggesting that the photochemical synthesis of vitamin D3 might not be significant in fish. It has been * To whom correspondence should be addressed . Abbreviations 7-DHC, 7-dehydrocholesterol; 25-OH-D3, 25-hydroxy vitamin D3; UV, ultraviolet; HPLC, high-performance liquid chromatography. (16) that UV exposure to the muscle of Katsuwonus pelamis (Skipjack) in vitro resulted in the conversion of provitamin D3 to vitamin D3 (20%), indicating that photochemical formation of vitamin D3 is possible in fish when exposed to UV light. However, direct evidence for the capability of fish to photosynthesize vitamin D needs to be established. This aspect was studied in the freshwater column feeder fish Tilapia mossambica (Tilapia) and reported in this paper.