STUDIES UPON THE PHYSIOLOGICAL ACTION OF HEMATOPORPHYRIN

Area of Science:

• Biochemistry
• Photobiology
• Physiology

Background:

• Hematoporphyrin is a photosensitizing agent.
• The physiological effects of hematoporphyrin combined with light exposure are not fully understood.
• Previous research suggests a role for natural pigments in photoprotection.

Purpose of the Study:

• To investigate the physiological effects of hematoporphyrin and light exposure in animal models.
• To determine if a transferable shock-inducing agent exists in the blood of affected animals.
• To explore the protective role of natural skin pigmentation against hematoporphyrin-induced photosensitivity.

Main Methods:

• Administration of hematoporphyrin to various animal models (mice, rats, cats, dogs).
• Controlled exposure to sunlight or artificial light, with some animals protected from light.
• Analysis of physiological parameters including blood pressure, body temperature, blood gas levels, and biochemical markers.
• Parabiosis experiments to assess the transferability of shock-inducing factors.

Main Results:

• Hematoporphyrin injection followed by sunlight exposure induced shock-like symptoms in cats, characterized by hypotension and hypothermia.
• In vitro and in vivo blood analysis revealed decreased oxygen and increased carbon dioxide levels under light exposure.
• Attempts to induce shock by transferring blood from affected animals were unsuccessful.
• Natural skin pigmentation provided some protection against sunlight-induced effects.

Conclusions:

• The combined action of hematoporphyrin and light induces significant physiological changes, supporting existing theories on their interaction.
• No evidence was found for a circulating factor that transmits hematoporphyrin shock.
• Natural skin pigment plays a physical protective role against photosensitization.